<template>
  <div>
    <div class="shopcart">
      <div class="content">
        <div class="content-left" @click="toogleList">
          <div class="logo-wrapper">
            <div class="logo" :class="{highlight: totalCount>0}">
              <i class="icon-shopping_cart" :class="{highlight: totalCount>0}"></i>
            </div>
            <div class="num" v-if="totalCount">{{totalCount}}</div>
          </div>
          <div class="price">￥{{totalPrice}}</div>
          <div class="desc">另需配送费￥{{deliveryPrice}}元</div>
        </div>
        <div class="content-right" @click="pay">
          <div class="pay" :class="totalPrice<minPrice?'not-enough':'enough'">{{payText}}</div>
        </div>
      </div>

      <div class="ball-container">
        <transition
          name="drop"
          v-for="(ball, index) in balls"
          :key="index"
          @before-enter="beforeDrop"
          @enter="dropping"
          @after-enter="afterDrop"
          v-bind:css="false"
        >
          <div class="ball" v-show="ball.isShow">
            <div class="inner inner-hook"></div>
          </div>
        </transition>
      </div>

      <transition name="fold">
        <div class="shopcart-list" v-show="listShow">
          <div class="list-header">
            <h1 class="title">购物车</h1>
            <span class="empty" @click="clearCart">清空</span>
          </div>
          <div class="list-content" ref="listContent">
            <ul>
              <li class="food" v-for="(food, index) in foodList" :key="index">
                <span class="name">{{food.name}}/{{food.count}}个</span>
                <div class="price">
                  <span>￥{{food.price}}</span>
                </div>
                <div class="cartcontrol-wrapper">
                  <cartcontrol :food="food" :update-food-count="updateFoodCount"></cartcontrol>
                </div>
              </li>
            </ul>
          </div>
        </div>
      </transition>
    </div>

    <transition name="fade">
      <div class="list-mask" v-show="listShow" @click="toogleList"></div>
    </transition>
  </div>
</template>

<script>
import BScroll from "better-scroll";
import Vue from "vue";
import cartcontrol from "../cartControl/cartControl.vue";

export default {
  name: "shopcart",
  props: {
    foodList: Array,
    deliveryPrice: Number,
    minPrice: Number,
    clearCart: Function,
    updateFoodCount: Function
  },
  data() {
    return {
      isShow: false,
      balls: [
        { isShow: false },
        { isShow: false },
        { isShow: false },
        { isShow: false },
        { isShow: false }
      ],
      droppingBalls: []
    };
  },
  computed: {
    totalCount() {
      return this.foodList.reduce((preTotal, food) => {
        return preTotal + food.count;
      }, 0);
    },
    totalPrice() {
      return this.foodList.reduce((preTotal, food) => {
        return preTotal + food.count * food.price;
      }, 0);
    },
    payText() {
      var minPrice = this.minPrice;
      var totalPrice = this.totalPrice;

      if (totalPrice === 0) {
        return `￥${minPrice}元起送`;
      } else if (totalPrice < minPrice) {
        return `还差￥${minPrice - totalPrice}元起送`;
      } else {
        return "去结算";
      }
    },
    listShow() {
      if (this.totalCount == 0) {
        this.isShow = false;
        return false;
      }

      // 如果是显示的状态
      if (this.isShow) {
        Vue.nextTick(() => {
          if (!this.scroll) {
            // 保存只创建一次
            this.scroll = new BScroll(this.$refs.listContent, {
              click: true
            });
          } else {
            // 不是第一次
            this.scroll.refresh(); // 刷新一个滚动(如果高度大于容器元素的高度, 形成滚动条)
          }
        });
      }

      return this.isShow;
    }
  },
  methods: {
    toogleList() {
      this.isShow = !this.isShow;
    },
    /**
     * 让一个隐藏的小球启动一个显示的动画--------------------------------------------------------------------------------------------
     */
    drop(startEl) {
      // 找到隐藏的小球
      const ball = this.balls.find(ball => !ball.isShow);
      // 显示它
      if (ball) {
        ball.isShow = true;
        ball.startEl = startEl;
        this.droppingBalls.push(ball);
      }
    },

    /*
      指定el的起始位置
       */
    beforeDrop(el) {
      // console.log("before()", Date.now());
      // 找到对应的ball
      const ball = this.droppingBalls.shift(); // 移除第一个

      var offsetY = 0;
      var offsetX = 0;
      // 计算
      const { left, top } = ball.startEl.getBoundingClientRect();
      const elLeft = 32;
      const elBottom = 22;
      offsetX = left - elLeft;
      offsetY = -(window.innerHeight - top - elBottom);

      // 指定transform样式
      el.style.transform = `translate3d(0, ${offsetY}px, 0)`;
      el.children[0].style.transform = `translate3d(${offsetX}px, 0, 0)`;

      // 保存ball
      el.ball = ball;
    },

    /*
      指定el的结束位置
       */
    dropping(el) {
      // 强制重排重绘
      var temp = el.clientHeight;
      // console.log("dropping()", Date.now());
      // 异步指定
      this.$nextTick(() => {
        // 指定transform样式
        el.style.transform = "translate3d(0, 0, 0)";
        el.children[0].style.transform = "translate3d(0, 0, 0)";
      });
    },
    /*
      隐藏el
       */
    afterDrop(el) {
      // console.log("afterDrop()", Date.now());
      // 必须延迟更新状态
      setTimeout(() => {
        el.ball.isShow = false;
      }, 400);
    },
    pay() {
      if (this.totalPrice >= this.minPrice) {
        alert(`支付${this.totalPrice + this.deliveryPrice}`);
      }
    }
  },
  components: {
    cartcontrol
  }
};
</script>

<style lang="stylus" rel="stylesheet/stylus">
@import '../../common/stylus/mixins.styl';

.shopcart {
  position: fixed;
  left: 0;
  bottom: 0;
  z-index: 50;
  width: 100%;
  height: 48px;

  .content {
    display: flex;
    background: #141d27;
    font-size: 0;
    color: rgba(255, 255, 255, 0.4);

    .content-left {
      flex: 1;

      .logo-wrapper {
        display: inline-block;
        vertical-align: top;
        position: relative;
        top: -10px;
        margin: 0 12px;
        padding: 6px;
        width: 56px;
        height: 56px;
        box-sizing: border-box;
        border-radius: 50%;
        background: #141d27;

        .logo {
          width: 100%;
          height: 100%;
          border-radius: 50%;
          text-align: center;
          background: #2b343c;

          &.highlight {
            background: rgb(0, 160, 220);
          }

          .icon-shopping_cart {
            line-height: 44px;
            font-size: 24px;
            color: #80858a;

            &.highlight {
              color: #fff;
            }
          }
        }

        .num {
          position: absolute;
          top: 0;
          right: 0;
          width: 24px;
          height: 16px;
          line-height: 16px;
          text-align: center;
          border-radius: 16px;
          font-size: 9px;
          font-weight: 700;
          color: #fff;
          background: rgb(240, 20, 20);
          box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.4);
        }
      }

      .price {
        display: inline-block;
        vertical-align: top;
        margin-top: 12px;
        line-height: 24px;
        padding-right: 12px;
        box-sizing: border-box;
        border-right: 1px solid rgba(255, 255, 255, 0.1);
        font-size: 16px;
        font-weight: 700;

        &.highlight {
          color: #fff;
        }
      }

      .desc {
        display: inline-block;
        vertical-align: top;
        margin: 12px 0 0 12px;
        line-height: 24px;
        font-size: 10px;
      }
    }

    .content-right {
      flex: 0 0 105px;
      width: 105px;

      .pay {
        height: 48px;
        line-height: 48px;
        text-align: center;
        font-size: 12px;
        font-weight: 700;

        &.not-enough {
          background: #2b333b;
        }

        &.enough {
          background: #00b43c;
          color: #fff;
        }
      }
    }
  }

  .ball-container {
    .ball {
      position: fixed;
      left: 32px;
      bottom: 22px;
      z-index: 200;
      transition: all 0.4s cubic-bezier(0.49, -0.29, 0.75, 0.41);

      .inner {
        width: 16px;
        height: 16px;
        border-radius: 50%;
        background: rgb(0, 160, 220);
        transition: all 0.4s linear;
      }
    }
  }

  .shopcart-list {
    position: absolute;
    left: 0;
    top: 0;
    z-index: -1;
    width: 100%;
    transform: translate3d(0, -100%, 0); /* 显示时的状态 */

    &.fold-enter-active, &.fold-leave-active {
      transition: all 0.5s;
    }

    &.fold-enter, &.fold-leave-active {
      transform: translate3d(0, 0, 0);
    }

    .list-header {
      height: 40px;
      line-height: 40px;
      padding: 0 18px;
      background: #f3f5f7;
      border-bottom: 1px solid rgba(7, 17, 27, 0.1);

      .title {
        float: left;
        font-size: 14px;
        color: rgb(7, 17, 27);
      }

      .empty {
        float: right;
        font-size: 12px;
        color: rgb(0, 160, 220);
      }
    }

    .list-content {
      padding: 0 18px;
      max-height: 217px;
      overflow: hidden;
      background: #fff;

      .food {
        position: relative;
        padding: 12px 0;
        box-sizing: border-box;
        border-1px(rgba(7, 17, 27, 0.1));

        .name {
          line-height: 24px;
          font-size: 14px;
          color: rgb(7, 17, 27);
        }

        .price {
          position: absolute;
          right: 90px;
          bottom: 12px;
          line-height: 24px;
          font-size: 14px;
          font-weight: 700;
          color: rgb(240, 20, 20);
        }

        .cartcontrol-wrapper {
          position: absolute;
          right: 0;
          bottom: 6px;
        }
      }
    }
  }
}

.list-mask {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 40;
  backdrop-filter: blur(10px);
  opacity: 1;
  background: rgba(7, 17, 27, 0.6);

  &.fade-enter-active, &.fade-leave-active {
    transition: all 0.5s;
  }

  &.fade-enter, &.fade-leave-active {
    opacity: 0;
    background: rgba(7, 17, 27, 0);
  }
}
</style>